<nav class="col-md-2" id="navbar-left" th:fragment="navbar" >
    <ul id="main_nav" >
        <li class="ul_outside"><a href="#"><img src="/img/左箭头.png"></a></li>
        <li class="ul_outside"><a href="#"><img src="/img/管理分组.png" class="img_left">管理通讯录<img src="/img/右箭头.png" class="img_right"></a>
            <ul class="ul_inside">
                <li><a href="http://localhost:8080/tel/new">新建联系人</a></li>
                <li><a href="http://localhost:8080/addGroup/new">新增分组</a></li>
                <li><a href="http://localhost:8080/login?logout">退出登录</a></li>
            </ul>
        </li>
        <li class="ul_outside"><a href="#"><img src="/img/首页菜单图标.png" class="img_left">管理分组<img src="/img/右箭头.png" class="img_right"></a>
            <ul class="ul_inside">
                <li><a href="http://localhost:8080/addGroup">查看/编辑分组</a></li>
            </ul>
        </li>
        <li class="ul_outside"><a href="#"><img src="/img/首页菜单图标.png" class="img_left">管理联系人<img src="/img/右箭头.png" class="img_right"></a>
            <ul class="ul_inside">
                <li><a href="http://localhost:8080/linkman/">查看/编辑联系人</a></li>
            </ul>
        </li>

    </ul>
</nav>